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The Mars Odyssey Gamma-Ray Spectrometer/Neutron Spectrometer/High Energy Neutron Detector has provided measurements of near-surface hydrogen, generally interpreted as resulting from water, in the equatorial and mid-latitudes. Water abundances as great as 10 % by mass are inferred. Although such high...
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ftciteseerx:oai:CiteSeerX.psu:10.1.1.569.8639 2023-05-15T16:38:20+02:00 tio Fbruce M. Jakosky A Michael T. Mellon A E. Stacy Varnes A William C. Feldman C William V. Boynton D Robert M. Haberle E The Pennsylvania State University CiteSeerX Archives 2005 application/pdf http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.569.8639 http://activetectonics.la.asu.edu/geomorph_seminar/Jakosky_et_al_icarus_2005.pdf en eng http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.569.8639 http://activetectonics.la.asu.edu/geomorph_seminar/Jakosky_et_al_icarus_2005.pdf Metadata may be used without restrictions as long as the oai identifier remains attached to it. http://activetectonics.la.asu.edu/geomorph_seminar/Jakosky_et_al_icarus_2005.pdf Mars Neutrons text 2005 ftciteseerx 2016-01-08T12:26:16Z The Mars Odyssey Gamma-Ray Spectrometer/Neutron Spectrometer/High Energy Neutron Detector has provided measurements of near-surface hydrogen, generally interpreted as resulting from water, in the equatorial and mid-latitudes. Water abundances as great as 10 % by mass are inferred. Although such high abundances could be present as adsorbed water in clays or water of hydration of magnesium salts, other measurements suggest that this is not likely. The spatial pattern of where the water is located is not consistent with a dependence on composition, topography, present-day atmospheric water abundance, latitude, or thermophysical properties. The zonal distribution of water shows two maxima and two minima, which is very reminiscent of a distribution that is related to an atmospheric phenomenon. We suggest that the high water abundances could be due to transient ground ice that is present in the top meter of the surface. Ice would be stable at tens-of-centimeters depth at these latitudes if the atmospheric water abundance were more than about several times the present value, much as ice is stable poleward of about ±60 ◦ latitude for current water abundances. Higher atmospheric water abundances could have resulted relatively recently, even with the present orbital elements, if the south-polar cap had lost its annual covering of CO2 ice; this would have exposed an underlying water-ice cap that could supply water to the atmosphere during southern summer. If this hypothesis is correct, then (i) the low-latitude water ice is unstable today and is in the process of sublimating and diffusing back into the atmosphere, and (ii) the current configuration of perennial CO2 ice being present on the south cap but not on the north cap might not be representative of the present epoch Text Ice cap Unknown |
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Mars Neutrons |
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Mars Neutrons Fbruce M. Jakosky A Michael T. Mellon A E. Stacy Varnes A William C. Feldman C William V. Boynton D Robert M. Haberle E tio |
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Mars Neutrons |
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The Mars Odyssey Gamma-Ray Spectrometer/Neutron Spectrometer/High Energy Neutron Detector has provided measurements of near-surface hydrogen, generally interpreted as resulting from water, in the equatorial and mid-latitudes. Water abundances as great as 10 % by mass are inferred. Although such high abundances could be present as adsorbed water in clays or water of hydration of magnesium salts, other measurements suggest that this is not likely. The spatial pattern of where the water is located is not consistent with a dependence on composition, topography, present-day atmospheric water abundance, latitude, or thermophysical properties. The zonal distribution of water shows two maxima and two minima, which is very reminiscent of a distribution that is related to an atmospheric phenomenon. We suggest that the high water abundances could be due to transient ground ice that is present in the top meter of the surface. Ice would be stable at tens-of-centimeters depth at these latitudes if the atmospheric water abundance were more than about several times the present value, much as ice is stable poleward of about ±60 ◦ latitude for current water abundances. Higher atmospheric water abundances could have resulted relatively recently, even with the present orbital elements, if the south-polar cap had lost its annual covering of CO2 ice; this would have exposed an underlying water-ice cap that could supply water to the atmosphere during southern summer. If this hypothesis is correct, then (i) the low-latitude water ice is unstable today and is in the process of sublimating and diffusing back into the atmosphere, and (ii) the current configuration of perennial CO2 ice being present on the south cap but not on the north cap might not be representative of the present epoch |
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The Pennsylvania State University CiteSeerX Archives |
format |
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Fbruce M. Jakosky A Michael T. Mellon A E. Stacy Varnes A William C. Feldman C William V. Boynton D Robert M. Haberle E |
author_facet |
Fbruce M. Jakosky A Michael T. Mellon A E. Stacy Varnes A William C. Feldman C William V. Boynton D Robert M. Haberle E |
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Fbruce M. Jakosky A |
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2005 |
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http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.569.8639 http://activetectonics.la.asu.edu/geomorph_seminar/Jakosky_et_al_icarus_2005.pdf |
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http://activetectonics.la.asu.edu/geomorph_seminar/Jakosky_et_al_icarus_2005.pdf |
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http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.569.8639 http://activetectonics.la.asu.edu/geomorph_seminar/Jakosky_et_al_icarus_2005.pdf |
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Metadata may be used without restrictions as long as the oai identifier remains attached to it. |
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